This invention relates to the repairing of radiators and heaters of the type found in automobiles, trucks and other vehicles and more particularly to improvements in apparatus for fixturing or positioning such devices with means to facilitate remounting and securing the radiator tank to the radiator header after repairs are made.
Radiators date back to the early existence of the automobile and while both the materials and manufacturing techniques used have been greatly improved, the basic radiator construction, which has changed little since the first models, includes tubes, fins and headers which make up a cored housing for dissipating heat in a well known manner and tanks with fittings and brackets for attachment to each end of the core. When either the cored structure or tank must be repaired due to leakage, blockage or the like, the tank is generally removed and later replaced.
Traditionally, radiator construction has utilized a brass tank soldered to a brass header which requires remelting or melting out to remove the tank and re-soldering to replace the tank. The construction and maintenance of brass tanks is labor intensive and costly and mid 1970's saw the advent of the plastic tank by which injection moulding technology made possible the production of a radiator tank in a matter of minutes. This new process requires the use of expensive molds and due to the rapidly gaining acceptance and success of the plastic tank for radiator construction, it can be anticipated that the use of the plastic tank will continue to increase.
Attaching plastic tanks to the radiator headers requires a different joining process than when attaching metal tanks by soldering. For this purpose, the header is provided with a circumscribing channel or trough for receiving a gasket against which the tank is placed. Flat, oval or O-ring gaskets are used and these must be compressed by a uniform pressure for a fluid tight seal. The standard rule of thumb for compressing the gaskets properly is to compress them forty percent of their normal thickness and since different thicknesses and types of material are used in gaskets, it is generally difficult to determine the exact amount of force required. The important factor in this regard, however, is that the pressure applied is uniform across the width of the radiator in order to insure the best results.
Once the gasket is properly compressed, a variety of mechanical means are available on different radiators to secure the tank for maintaining the seal. Some Japanese and European radiator makers use separate crimping strips which lock under the gasket trough and over the lip of the tank. A Dutch company uses a process known as Nerfix which has strips that are pressed into header slots in a door latch fashion and another method includes the use of a dimpled header which has depressions that lock over the lip of the tank. The more popular fastening means, however, is the crimping tab which is in widespread use. This method utilizes serially arranged tabs integral with the header which are pressed up and over the lip of the plastic tank for a fluid seal engagement and which must be lifted up to release the seal and provide clearance for removal of the tank. I have observed that many fixturing machines now in use hold the radiator with parallel grooved bars that block access to all but the top part of the tab so that when the tab is lifted, all of the stress is placed at one radius point of the tab. It is thus not unusual for one or more of the tabs to break since on many radiators needing repairs the tabs have been in service for several years and have lost some of their original strength due to thermal expansion and contraction as well as prior bending and rebending and it is commonly known that if two or more tabs in a row break, the radiator cannot be easily repaired.
Many radiator repair and services devices used on brass tanks are not readily adaptable to the new plastic tanks and several new devices have been designed to address the problems posed by the plastic tanks. Most of these are large, heavy and costly and are not sufficiently versatile to efficiently and economically meet all of the requirements for making needed repairs. Some require the use of special tab tools and some include mechanical pressure elements such as air cylinders which in some instances have substantially damaged the tanks and headers due to excessive pressure or sudden or unexpected activation. In addition, some of these new devices require re-arrangement or replacement of parts to adapt to either brass or plastic tanks and, in general, have not satisfied the requirement of the small repair shop for a simple, convenient and efficient radiator repair apparatus.
With the foregoing observations in mind, it is one of the objects of this invention to provide an apparatus for fixturing or positioning the header of a repaired radiator with improved, efficient and economical means for remounting and securing the radiator tank to the header.
Another object is to provide an apparatus of the above class that can be used with equal efficiency on either brass or plastic radiator tanks.
A further object is to provide an apparatus as characterized that includes manually operated screw clamp assemblies for applying pressure to the top of the tank against the header.
Still another object is to provide said screw clamp assemblies with adjustable tank engaging pads and with the capability of moving transversely of the tank into selective detent locked positions to afford easy access to the tank in mounting it to said apparatus.
Another object is to provide an apparatus as characterized with the capability to receive and release a selective number of screw clamp assemblies according to the number required.
Yet another object is to provide each screw clamp assembly with an integral pressure calibrated spring means and pressure indicating indicia to provide uniform pressure on the tank throughout its length.
Another object to to provide an apparatus of the above class that is adjustable to accommodate various widths of radiators.
Still another object is to provide a radiator fixturing device which will support a tab type header for a plastic radiator tank to afford full and easy access to the tabs so they can be lifted or crimped with a minimum of stress and where the stress in lifting is distributed throughout the tab.
A further object is to provide an apparatus as described that is designed to be suspended from an overhead support and thus require no floor space and is preferably suspended from a circular support to afford 360.degree. rotation of the radiator from a fixed position of the operator.
Another object is to provide an apparatus of the above class that is sufficiently light in weight to be easily stored or transported.
A further object is to provide a radiator fixturing device as characterized that permits the use of any available conventional tab tool.